Systems and methods for generating electrical energy

ABSTRACT

A vertical twin rotor water turbine apparatus and method for extracting energy from a flow of water is described herein. The described apparatus delivers favorable performance by virtue the operation of a novel configuration of a plurality of central cores with at least one blade member extending from each core and flow directors to increase the effectiveness and efficiency of said device.

RELATED APPLICATIONS

This application claims priority as a divisional of U.S. applicationSer. No. 16/966,033, filed Jul. 30, 2020, titled “Systems and Methodsfor Generating Electrical Energy,” which is scheduled to issue as U.S.Pat. No. 11,162,471 on Nov. 2, 2021.

FIELD

The disclosure relates to the field of electrical energy generation, andmore specifically to systems and methods of generating electrical energyusing a vertical twin rotor water turbine.

BACKGROUND

The world demand for energy is ever increasing thereby giving rise tothe need to develop and continually improve energy-extractingtechnologies. Renewable energy sources are favorable due to theirrelatively low environmental impact. One example of a renewal energysource is a hydro-electric generating device, commonly referred to as awater turbine.

Various configurations of water turbine exist for extracting energy froma flow of water. However, such devices can be difficult to maintain asthey are typically submerged under water, thereby imposing harshconditions on the mechanical components essential to the devices'vitality. Furthermore, there is ongoing pressure to increase theeffectiveness and efficiency of these devices and decrease the minimumflow speed requirements for their operability such that a largerproportion of our planet's running water sources may be harnessed fortheir energy.

These deficiencies, and others, are addressed by the various embodimentsdescribed in the present disclosure.

SUMMARY

In an aspect, the present disclosure provides an apparatus forextracting energy from a flow of water, the apparatus comprising: aplurality of central cores, each supported at a first and second end,each core rotatable about a substantially vertical axis; at least oneblade member extending from each of the central cores for engaging withthe flow of water to cause rotation of the central cores; and, at leastone primary flow director positioned at a leading end of the apparatusfor directing incoming water flow toward a predetermined region alongeach of the at least one blade members, wherein the plurality of coresis positioned behind the at least one primary flow director.

In another aspect, the present disclosure provides a blade for use withan energy-generating turbine, the turbine having a central rotatingmember, the blade having a ram surface and a lift-surface, the bladecomprising: an inner portion proximate the central rotating member; acentral portion beginning at a distal end of the inner portion; and, anouter portion beginning at a distal end of the central portion andterminating in a sharp tip; wherein the central portion is curved toinduced lift to the non-ram side of the blade; and wherein a curvatureof the outer portion at the tip substantially corresponds to a curvatureof a circular path travelled by the tip of the blade during rotation ofthe central rotating member.

In another aspect, the present disclosure provides a method to extractenergy from a flow of water, comprising the steps of: deploying anapparatus into a water mass, the apparatus comprising: a plurality ofcentral cores, each supported at a first and second end, each corerotatable about a substantially vertical axis; at least one blade memberextending from each of the central cores for engaging with the flow ofwater to cause rotation of the central cores; and, at least one primaryflow director positioned at a leading end of the apparatus for directingincoming water flow toward a predetermined region along each of the atleast one blade members, wherein the plurality of cores is positionedbehind the at least one primary flow director; operating the apparatusto generate energy from the flow of water; and, transmitting the energyto power an electrical device.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures serve to illustrate various embodiments offeatures of the disclosure. These figures are illustrative and are notintended to be limiting.

FIG. 1 is a top view of an energy extraction apparatus according to anembodiment of the present disclosure;

FIG. 2 is a perspective view of the energy extraction apparatus shown inFIG. 1;

FIG. 3 is a top view of the primary flow director, the central cores,the foil and secondary flow directors of the energy extraction apparatusshown in FIG. 1;

FIG. 3A is a top view of the primary flow director, foil, secondary flowdirectors and a variant of the central cores of the energy extractionapparatus shown in FIG. 1;

FIG. 4 is a top view of the central cores and blade members, inisolation, of the energy extraction apparatus of FIG. 1;

FIG. 5 is a perspective view of yet another embodiment of the presentdisclosure;

FIG. 6 shows a cross-section of a blade member according to anotherembodiment of this disclosure;

FIG. 7 shows a perspective view of a core having two blade members asdescribed in the embodiment of FIG. 6;

FIG. 8 shows a perspective view of a core having three blade members asdescribed in the embodiment of FIG. 6;

FIG. 9 shows a perspective view of a core having four blade members asdescribed in the embodiment of FIG. 6;

FIG. 10 shows a perspective view of a core having six blade members asdescribed in the embodiment of FIG. 6;

FIG. 11 shows a perspective view of a core having eight blade members asdescribed in the embodiment of FIG. 6;

FIG. 12 shows a perspective view of a core having ten blade members asdescribed in the embodiment of FIG. 6;

FIG. 13 is a front view of an energy extraction apparatus havingdihedral fins according to another embodiment of the present disclosure;

FIG. 14 is a side view of the energy extraction apparatus havingdihedral fins according to another embodiment of the present disclosure;

FIG. 15 is a top view of the energy extraction apparatus as described inthe embodiment of FIG. 14;

FIG. 16 is a perspective view of the energy extraction apparatussubmerged in a body of water as described in the embodiment of FIG. 14;

FIG. 17 is a side view of the energy extraction apparatus submerged in abody of water as described in the embodiment of FIG. 14;

FIG. 18 is a front perspective view of an energy extraction apparatushaving dihedral fins and a rear fin according to yet another embodimentof the present disclosure;

FIG. 19 is a rear perspective view of the energy extraction apparatus asdescribed in the embodiment of FIG. 18;

FIG. 20 is a rear view of the energy extraction apparatus as describedin the embodiment of FIG. 18;

FIG. 21 is a side view of the energy extraction apparatus as describedin the embodiment of FIG. 18;

FIG. 22 is a rear perspective view of the energy extraction apparatuspartially submerged in a body of water as described in the embodiment ofFIG. 18;

FIG. 23 is a front perspective view of an energy extraction apparatusfor shallow water, according to another embodiment of the presentdisclosure;

FIG. 24 is a front perspective cutaway view of the energy extractionapparatus described in the embodiment of FIG. 23;

FIG. 25 is a top view of the front flow director of the energyextraction apparatus described in the embodiment of FIG. 23;

FIG. 26 is a top cutaway view of the energy extraction apparatusdescribed in the embodiment of FIG. 23;

FIG. 27 is a top cutaway view of one of the central cores of the energyextraction apparatus described in the embodiment of FIG. 23;

FIG. 28 is a front perspective view of the energy extraction apparatusdescribed in the embodiment of FIG. 23 secured to a floor stabilizer;

FIG. 29 is a side view of the energy extraction apparatus described inthe embodiment of FIG. 28 and secured to the water floor;

FIG. 30 is a top view of a configuration of the front flow director,central cores and secondary flow directors when water flows in directionY, according to an embodiment of the present disclosure;

FIG. 30A is a top view of a configuration of the front flow director,central cores and secondary flow directors when water flows in directionY′, according to an embodiment of the present disclosure;

FIG. 30B is a top view of a configuration of the front flow director,central cores and secondary flow directors, the front flow director andsecondary flow directors having stoppers, according to an embodiment ofthe present disclosure;

FIG. 30C is a top view of a configuration of the front flow director,secondary flow directors and a plurality of central cores in asubstantially V-shaped configuration, according to an embodiment of thepresent disclosure;

FIG. 31 is a top perspective view of an energy extraction apparatus forshallow water, according to yet another embodiment of the presentdisclosure;

FIG. 32 is a top cross-sectional perspective view of the energyextraction apparatus as described in FIG. 31, the cross-section beingtaken through the center of the energy extraction apparatus;

FIG. 33 is a cross-sectional perspective view of the energy extractionapparatus as described in FIG. 31, the cross-section being taken throughthe shield;

FIG. 34 is a top cross-sectional view of the energy extraction apparatusas described in FIG. 31;

FIG. 35 is a top perspective view of an energy extraction apparatus forshallow water, according to yet another embodiment of the presentdisclosure;

FIG. 36 is a cross-sectional perspective view of the energy extractionapparatus as described in FIG. 35, the cross-section being taken throughthe center of the energy extraction apparatus;

FIG. 37 is a cross-sectional perspective view of the energy extractionapparatus as described in FIG. 35, the cross-section being taken throughthe shield;

FIG. 38 is a top cross-sectional view of the energy extraction apparatusas described in FIG. 35;

FIG. 39A is a top view of a configuration of the front flow director andcentral cores, according to another embodiment of the presentdisclosure;

FIG. 39B is a top view of a configuration of the front flow director andcentral cores, according to another embodiment of the presentdisclosure;

FIG. 39C is a top view of a configuration of the front flow director andcentral cores, according to another embodiment of the presentdisclosure;

FIG. 39D is a top view of a configuration of the front flow director andcentral cores, according to another embodiment of the presentdisclosure;

FIG. 39E is a top view of a configuration of the front flow director andcentral cores, according to another embodiment of the presentdisclosure;

FIG. 39F is a top view of a configuration of the front flow director andcentral cores, according to another embodiment of the presentdisclosure;

FIG. 40 is a top perspective view of an energy extraction apparatus forshallow water without an upper frame, according to yet anotherembodiment of the present disclosure;

FIG. 41 is a top perspective view of an energy extraction apparatus forshallow water, according to yet another embodiment of the presentdisclosure;

FIG. 42 is a side view of the energy extraction apparatus for shallowwater shown in FIG. 41;

FIG. 43 is a perspective view of the energy extraction apparatus forshallow water shown in FIG. 41, with shield 6035 omitted;

FIG. 44 is a top cutaway view of a bladed core, according to anotherembodiment of the present disclosure;

FIG. 45 is a perspective cutaway view of the bladed core as shown inFIG. 44;

FIG. 46 is a top cutaway view of a single blade of the bladed core asshown in FIG. 44; and,

FIG. 47 is a block diagram representing the steps of a method forextracting energy from a flow of water using the apparatus embodimentsdescribed herein, in accordance with an embodiment of the presentdisclosure.

DETAILED DESCRIPTION

The following embodiments are merely illustrative and are not intendedto be limiting. It will be appreciated that various modifications and/oralterations to the embodiments described herein may be made withoutdeparting from the disclosure and any such modifications and/oralterations are within the scope of the contemplated disclosure.

With reference to FIGS. 1 and 2 and according to an embodiment of thepresent disclosure, an energy extraction apparatus 10 is shown. In thisembodiment, apparatus 10 is comprised of two central cores 15, 17. Eachof the central cores 15, 17 are supported at opposing ends such thatthey are permitted freedom of rotation about their respective centralaxes Z1, Z2. In operation, the cores 15, 17 are positioned such thattheir axes of rotation are vertical or substantially vertical. In theembodiment illustrated, the two cores 15, 17 are supported by suitablebearings (not shown) and frame 12. Persons of ordinary skill in the artwill appreciate that the supporting frame 12 may take on variousconfigurations provided that it serves to maintain the necessary spatialrelationship between the various components of the apparatus 10.

Each core 15, 17 has a plurality of blade members 20, 22 that extend outradially from the center of the cores 15, 17. In the preferredembodiment, the apparatus 10 is illustrated as having three blades percore 15, 17; however, the person skilled in the art will appreciate thata lesser or greater number of blades per core may be used withoutdeparting from this disclosure. As water flows in direction Y toward andthrough the apparatus 10, forces generated by the water on the blademembers 20, 22 cause a rotation of the cores 15, 17. In the embodimentillustrated and from the vantage point depicted in FIG. 1, water flowingin direction Y would cause core 15 to rotate counter-clockwise and core17 to rotate clockwise. The resulting rotational energy of the cores 15,17 may then be converted to electricity using a combination of gearboxesand generators, as necessary, that are commonly known in the art. Forgreatly simplicity, gearboxes and generators have not been included inthe figures.

A suitable combination of power transmission components may be used toensure the synchronization of the rotation of the cores 15, 17 and avoidphysical contact between the blade members 20, 22. For example,combination of chain 24 and sprockets may be used to achieve thesynchronization of the bladed cores 15, 17 in opposite directions. Thoseskilled in the art would appreciate that other suitable combinations ofpower transmission components may be used to synchronize rotation of thecores 15, 17.

Apparatus 10 comprises numerous elements that help to increase theoverall coefficient of power of the system. These elements will now bedescribed with continued reference to FIGS. 1, 2 and 3. A primary flowdirector 30 is positioned at a leading end 35 of the apparatus 10. Asshown, primary flow director 30 is held in position by frame 12. Theprimary flow director 30 serves to direct incoming water flow in such away to maximize the resulting rotational energy of the cores 15, 17.Preferably, incoming water flow is directed to a stagnation point of thebladed core 15, 17. As known in the art, when a static object is placedin the path of a fluid flow, the stagnation point is the point along theobject that separates fluid flowing to one side of the object from fluidflowing to the other side of the object. In the case of the rotatingcores 15, 17 and blade members 20, 22 described herein, the stagnationpoint will change with the rotational position of the blade members 20,22 as well as with variations of the direction of the fluid flow. Assuch, the stagnation point will be continuously changing duringoperation of the apparatus 10. Through experimentation, applicant hasfound it desirable to direct incoming fluid flow toward an area alongthe blade members 20, 22 within the speckled zone depicted as B in FIG.4. The boundaries of zone B consist of two substantially parallelplanes. The first plane P1 is the plane that contains the rotationalaxis of the core in question (in this example core 15) and issubstantially parallel to the natural flow direction Y. The second planeP2 is a plane resulting from a lateral translation of plane P1 by adistance of 0.5*R in a direction normal to axis Z1 of the core inquestion 15 toward the axis Z2 of the other core (core 17 in thisexample). Distance R is defined as the radius of the circumferentialpath travelled by the tips of the blade members 20 of the core inquestion 15 during rotation.

With continued reference to FIGS. 1, 2 and 3, secondary flow directors40, 42 are shown secured to the frame 12 and positioned next to and tothe outside of the rotational periphery of each of the bladed cores 15,17. The secondary flow directors 40, 42 serve to corral peripheralincoming fluid flow (via surfaces 95, 97) and direct it toward the blademembers 20, 22 to enhance the rotation-inducing forces experienced bythe blade members 20, 22. Secondary flow directors 40, 42 also serve tocontain fluid flow (via surfaces 96, 98) exiting the rotation of theblade members 20, 22 downstream of the rotational axes. Containing fluidflow exiting the apparatus 10 helps to reduce drag on the apparatus 10by facilitating reattachment of the flow downstream. Reattachment ofdownstream flow may be further induced using a reattachment member suchas foil 50. Foil 50 is a structural member having substantially the sameheight as the cores 15, 17 and blade members 20, 22. Foil 50 ispositioned at a rear end 55 of the apparatus 10 (downstream with respectto the cores 15, 17) and serves to reattach fluid flowing from the blademembers 20, 22, thereby reducing drag and increasing the coefficient ofpower of the system. Applicant has determined that a teardrop geometryresulting in a symmetrical airfoil is preferred. The person of ordinaryskill in the art, however, will appreciate that reduction of drag at thetail end of the apparatus may be accomplished by similar structures ofvarying geometries other than the teardrop illustrated in the preferredembodiments.

With reference to FIG. 2, each core 15, 17 of apparatus 10 may beconnected to a generator (not shown) via shafts 60, 62 projecting alongthe rotational axes Z1, Z2 of the cores 15, 17. The shafts 60, 62 may becoupled to the cores 15, 17 using, for example, various couplingconfigurations, keyless locking devices, or other suitable means knownto the person of ordinary skill in the art. The generators (not shown)would serve to convert the rotational energy of the cores 15, 17 intoelectricity. The ordinary skilled person would appreciate that althoughshafts 60, 62 are described herein as components separate from the cores15, 17, the cores 15, 17 may alternatively be manufactured withprotruding shafts built-in (for example, each core and protruding shaftbeing a unitary molded part).

The described embodiments of energy extraction device may be configuredin practice in an advantageous way that allows for one or many of themechanical components of the apparatus to be free from continuouscontact with water. For example, apparatus 10 may be suspended from oneor more buoyant structures 66, 68 such that the generators and gearboxes(not shown) lie above the surface level of the fluid, and the cores 15,17 and corresponding blade members 20, 22 lie below the fluid surface.The gearboxes and generators may be housed inside the buoyant structures66, 68, in which case the buoyant structures 66, 68 would also serve toshelter those components from the elements. The embodiment illustratedin FIGS. 1 and 2 shows the upper portion of the frame 12, including themeans for synchronizing rotation of the cores 15, 17, and any necessarysupport bearing and coupling mechanisms, in close proximity to the cores15, 17. However, the upper frame 12 may alternatively serve as thebuoyant structure and may be configured such that the bearings,couplings, synchronizing means and other mechanical components arefurther from the fluid surface. FIG. 13 illustrates such an alternateembodiment of the energy extraction apparatus and will be furtherdescribed below.

With specific reference to FIG. 3, the relative positioning andcross-sections of the cores 15, 17, the primary flow director 30, thesecondary flow directors 40, 42, and the foil 50 are shown. The frame 12and other components of the apparatus have been omitted for ease ofillustration. The preferred cross-section of the primary flow director30 is a crescent-moon shape, having a convex leading surface 70 and aconcave trailing surface 75. The convex leading surface 70 of theprimary flow director 30 serves to split the incoming flow of fluiddenoted by arrow Y and direct it toward a desirable predeterminedportion (described in greater detail above) of the blade members 20, 22.Applicant has determined that the presence of lips 80 at the lateralextremities of the primary flow director is desirable as the lips helpto release flow adhesion at the extremities of the curved flow directoredges directing flow into the blades 20, 22, optimizing power bydirecting flow slightly outwards directly into the blade face, therebyincreasing the performance of the apparatus. The primary flow director30 is positioned at the leading end 35 of the apparatus, ahead of thecores 15, 17 and blade members 20, 22. A person skilled in the art wouldappreciate that although the present disclosure describes a singleprimary flow director 30 that is generally crescent-moon shaped, thenumber, shape and size of the primary flow director 30 can be variedprovided that it serves to direct incoming fluid flow toward thepredetermined location along the blade members. A central dotted line Xis shown to denote the position of the downstream-most point of thecurved front faces 95, 97 relative to the central cores 15, 17.Positioning the secondary flow directors 40, 42 such that the frontfaces 95, 97 terminate at a point that is upstream relative to therotational axes Z1, Z2 of the cores 15, 17 has been found to have apositive effect on the coefficient of power of the apparatus.

With reference to FIG. 3A, the components (the primary flow director 30,the secondary flow directors 40, 42, and the foil 50) that weredescribed in FIG. 3 are shown with an alternate embodiment of thecentral bladed cores 15 a, 17 a. In this alternate embodiment, thecentral core 15 a is comprised of exactly two blades 20 a, 20 b, 20 cwhile central core 17 a is also comprised of exactly two blades 22 a, 22b, 22 c. As shown, the central cores 15 a, 17 a are preferablysynchronized such that the blades 20 a, 20 b, 20 c are substantially ina horizontal plane, while the blades 22 a, 22 b, 22 c are substantiallyin a vertical plane. In other words, the central cores 15 a, 17 a areoffset by approximately 90-degrees. This relative 90-degree offset ofone central core 15 a with respect to the other central core 17 a,ensures that the blades 20 a, 20 b, 20 c and 22 a, 22 b, 22 c do not hitone another during rotation. In this embodiment, the secondary flowdirectors 40, 42 are positioned behind the center of the central cores15 a, 17 a, as depicted by the horizontal stippled line “A”, and help tocorral peripheral incoming fluid flow and direct it toward the blademembers 20 a, 20 b, 20 c, 22 a, 22 b, 22 c to enhance therotation-inducing forces experienced by the blade members 20 a, 20 b, 20c, 22 a, 22 b, 22 c.

With reference to FIG. 4, the relative positioning of the cores 15, 17in a preferred embodiment will now be described. The tips of the blademembers of each rotating core 15, 17 create a circumferential path. Asshown, the cores 15, 17 are positioned relative to one another such thattheir circumferential paths overlap. A preferred range of circle overlapbetween each of the bladed cores has been determined to be between 50%and 80% of radius R (i.e., a preferred range for the distance betweenthe axes of rotation of the cores Z1, Z2 has been determined to bebetween 1.5*R and 1.2*R).

FIG. 5 shows an alternative embodiment of the present disclosure whereenclosure plates 67, 69 are used to “bookend” the cores (not shown) andblade members (not shown). The use of these plates helps to maximize theenergy extracted from incoming fluid that comes into contact with theblade members (not shown) by preventing the escape of the fluid from theupper and lower extremities of the apparatus 10. The plates 67, 69 maybe shaped like two side-by-side circular discs merged together to form apeanut-like shape. The diameters of the disc portions of the plates mayvary; however, using discs with a radius of at least 125% of radius Rhave been shown favorable results with respect to the coefficient ofpower of the apparatus 10. Although the present embodiment discloses twocores, a worker skilled in the art would appreciate that a combinationof multiple dual-core systems would similarly be within the scope ofthis disclosure.

FIG. 6 shows a cross sectional blade geometry that has been found toexhibit desirable properties as a turbine blade. That is, a blade 85with the illustrated cross section has been shown to induce loweramounts of ram drag and higher amounts of lift when placed in the pathof a fluid flow. The blade 85 cross-section generally consists of a coreportion 87 consisting of a point that defines the blade's center ofrotation, and a blade portion 90. The blade portion 90 is generallydefined by a curvilinear impact side 92 and a curvilinear trailing side94, both originated from the core portion 87 and converging to a point,sometimes referred to as tip end 96, at some distance away from thecenter of rotation point. The angle between the two sides of the blade90 at the tip end 96 is minimized, thereby minimizing the thickness ofthe blade portion 90 at its tip end 96 and producing a blade 85 having asharp knife-edge extremity. The trailing side 94 of the blade portion 90of the blade 85 is mostly flat, thereby increasing the lift experiencedby the blade 85 during rotation. The blade portion 90 of this embodimentis further configured such that the tip end 96 of the blade portion 90closely matches the circumferential path defined by the travel of thetip end 96 of the rotating blade 85. In other words, a first linedefined by a point at the tip end 96 of the blade portion 90 and a pointalong the impact side 92 just prior to the tip end 96 is as closelycolinear as possible with the tangent of the circumferential path at thetip end 96 of the blade portion 90. Similarly, a second line defined bya point at the tip end 96 of the blade portion 90 and a point along thetrailing side 94 just before the tip 96 is as closely colinear aspossible with the tangent of the circumferential path at the tip end 96of the blade 85.

FIGS. 7, 8, 9, 10, 11 and 12 show cross-sectional views of alternateembodiments of cores having two, three, four, six, eight and ten of theblade portions illustrated in FIG. 7, respectively.

With reference to FIGS. 13, 14, 15, 16 and 17 and according to anotherembodiment of the present disclosure, an energy extraction apparatus 210that includes dihedral stability plates 215, 220 is shown. The stabilityplates 215, 220 are positioned at a lower end of the apparatus 210 andsecured via frame 212 and have an upward and outward angle with respectto the apparatus 210. As such, the stability plates 215, 220 help tomaintain the apparatus in a desirable orientation with respect to thedirection of water flow Y and optimize the performance of the apparatus210. In a similar fashion to the embodiment shown in FIGS. 1 and 2,apparatus 210 is equipped with a foil 222 positioned at the rear end ofthe apparatus 210. Foil 222 also may serve to help maintain the optimalorientation of the apparatus with respect to the water flow. Thestability plates 215, 220 and foil 222 may also serve to reduce unwantedagitation of the apparatus 210 during operation, brought on by minorvariations in water flow direction. To secure the apparatus 210generally within the flow of water, the apparatus 210 may for example betethered to the ocean floor by means of a cable 230 attached at one endto a connection point 225 of the apparatus 210, and at the other end toa heavy object 235 (as specifically shown in FIG. 16) such as a concreteblock resting on the ocean floor. In this embodiment, the entireapparatus 210 is configured to be buoyant and therefore biased towardthe surface of the water. Buoyancy may, for example, be achieved byselecting a suitable material for the construction of the frame orthrough the incorporation of dedicated buoyancy inducing elements (e.g.,263, 264) that may be positioned at the upper end of the apparatus 210and below the generators 266, 268.

As part of an alternative configuration, the apparatus may be configuredsuch that the main body (i.e., the bladed cores) is non-buoyant and theapparatus is suspended from above from a fixed structure such as, forexample, a rig similar to that typically used in offshore drilling. Anenergy extraction apparatus described herein may be suspended from sucha structure using one or more cables. In this type of alternativeconfiguration, buoyancy-inducing elements 263, 264 may still be used andmay be configured such that they induce buoyancy to generators locatedat an upper end of the apparatus but not to the remainder of theapparatus. Such a buoyancy configuration, along with a mechanism toallow vertical movement of the generators independent of the remainderof the apparatus, would help to prevent submersion of the generatorsthat may be caused by tidal activity or large rolling swells in the bodyof water. The vertical freedom of the generators may be achieved, forexample, by affording the portion of the frame (260, 262 in FIG. 13)extending from the top of the bladed cores to the generators a suitableamount of telescoping ability. The telescoping ability may be provided,for example, through the use of a square shaft with mating square hollowframe configuration for the portions of the frame 260, 262 extendingbetween the bladed cores of the apparatus and the generators.Alternatively, a commonly available double telescoping PTO drive shaftmay be used to afford the generators a desired amount of verticalfreedom. With such a configuration, a rising tide would not submerge thegenerators because the buoyancy-inducing elements would cause thegenerators to rise with the tide.

With reference to FIGS. 18, 19, 20, 21 and 22 and according to yetanother embodiment of the present disclosure, an energy extractionapparatus 310 with dihedral fins 315, 320 and rear stabilizing fin 323is shown. The dihedral fins 315, 320 are similarly configured todihedral fins 215, 220 that were earlier described with reference toFIGS. 13, 14, 15, 16 and 17. Rear fin 323 is positioned at the rear endof the apparatus 310, extends rearwardly therefrom, and has asubstantially planar paddle portion 333. Conceptually similar to aweather vane, the stabilizing fin 323 may be used to help mitigateunwanted yaw of the apparatus 310 when the apparatus 310 is positionedin a body of water, and to further help maintain a desirable orientationof the apparatus with respect to the water flow direction. Apparatus 310is also comprised of a frustum-shaped tower frame 328 projectingupwardly from an upper portion of the central cores. Tower frame 328 maybe configured to provide buoyancy to the apparatus to bias the apparatus310 and toward the surface of the water. Apparatus 310 may be tetheredto an anchoring block 335 by means of a cable 330. FIG. 22 shows anexample of the apparatus 310 biased toward the surface in a body ofwater and secured by tether to the ground. The length of the cable 330may be selected such that the generator or generators at the top of theapparatus are maintained generally above the water's surface.

With reference to FIGS. 23 and 24, another embodiment of the presentdisclosure will now be described. Apparatus 1010 is generally comprisedof a frame 1012, the frame 1012 preferably secured to at least twocentral cores 1015, 1017 and a primary flow director 1030. The twocentral cores 1015, 1017 are each further comprised of at least oneblade member 1020 a, 1022 a that extends radially from the center of thecentral cores 1015, 1017. In this embodiment, the apparatus 1010 isshown having three blades (e.g., 1020 a, 1020 b, 1020 c, 1022 a, 1022 b,1022 c) per core; however, a person skilled in the art would appreciatethat more or less than three blades may be used. As water flows indirection Y toward and through the apparatus 1010, forces generated bythe water on the impact (or ram) surface of blade members 1020 a, 1020b, 1020 c, 1022 a, 1022 b, 1022 c cause a rotation of the central cores1015, 1017. Additional forces on the blades 1020 a, 1020 b, 1020 c, 1022a, 1022 b, 1022 c, which will be described further below, alsocontribute to inducing rotation of the cores. In the embodiment shown inFIGS. 23 and 24, water flowing in direction Y would cause core 1015 torotate counter-clockwise and core 1017 to rotate clockwise. Theresulting rotational energy of the central cores 1015, 1017 may then beconverted to electricity using a combination of mechanical components(e.g., gearboxes and generators), as necessary. Such mechanicalcomponents may include belt or chain drives, power take-ups, or othersuitable components generally known in the art. For simplicity,gearboxes and generators have not been included in the figures.

The apparatus 1010 comprises numerous elements that help to increase theoverall coefficient of power of the system. For example, a primary flowdirector 1030 may be positioned at a leading end 1035 of the apparatus1010. The primary flow director 1030 may be secured to the frame 1012 toensure its proper positioning relative to the bladed cores 1015, 1017.The primary flow director 1030 serves to direct incoming water flow insuch a way to maximize the resulting rotational energy of the centralcores 1015, 1017. The primary flow director 1030 is further comprised oftwo lips 1080 positioned at the lateral extremities of the primary flowdirector 1030. These lips 1080 help to release flow adhesion at theextremities of the curved flow director edges directing flow into theblades 1020 a, 1020 b, 1020 c, 1022 a, 1022 b, 1022 c, contributing toan increased coefficient of power for the apparatus. Preferably,incoming water flow is directed to a stagnation point of the centralcores 1015, 1017, as similarly described previously with respect to theembodiment shown in FIGS. 1 to 4.

FIG. 25 shows a top view of the primary flow director 1030 of FIG. 24.Primary flow director 1030 is shown generally arrow-shaped, having aV-shaped front portion 1040 and lips 1080, which serve to re-direct theincoming water flow Y outwardly and toward a desired point on the blademembers, as previously described. As shown in FIG. 24, the centralportion 1037 of primary flow director 1030 may be configured with acurvature complimentary to that of the path travelled by the tips of theblades. FIG. 39A shows a top view of bladed cores 2015, 2017, and afront flow director 2030 similar to the one shown in the embodiment inFIG. 24. FIGS. 39B, 39C, 39D, 39E and 39F show alternative embodimentswith possible variants to the central portion and trailing end of thefront flow director, including a line shape as shown in FIG. 39B, an arcshape as shown in FIG. 39C, a triangle shape as shown in FIG. 39D, asquare shape as shown in FIG. 39E, or a trailing funnel-shape as shownin FIG. 39F.

A preferred spatial configuration of the bladed cores of this embodimentwill now be described with reference to FIGS. 26 and 27. Similar to theembodiment shown in FIG. 4, a distance “R” is defined by the radius ofthe circumferential path travelled by the tips (e.g., 1050 or 1052) ofthe blade members of the cores. The circumferential blade tip paths ofadjacent bladed cores (shown in FIG. 26 as dotted circles 1051 and 1053)are separated by a distance “D” as shown in FIG. 26. In a preferredembodiment, the central cores are spaced apart such that the distance“D” between the blade tip paths is between 1 and 4 times the radius “R”.

FIGS. 28 and 29 show how the embodiment of FIGS. 23 and 24 may besecured to a waterbed floor using a water floor stabilizer 1060. Thewater floor stabilizer 1060 has legs 1062 of variable lengths to besecured to the water floor 1065 to provide stability to the apparatus1010 in shallow water. Adjustability in the legs 1062 allows foraccommodation of an uneven waterbed floor and helps to ensure theapparatus 1010 is maintained in an even, horizontal position asspecifically shown in FIG. 29.

With reference to FIGS. 30, 30A and 30B, and according to an alternateembodiment of the present disclosure, the primary flow director 2030 maybe rotationally adjustable, for example, about a pivot axis 2050. Thepivot axis 2050 is positioned at a first end (or leading end) of theprimary flow director 2030. By virtue of its pivotability, the frontflow director 2030 is able to adjust to the conditions of the incomingwater flow and core rotation to help ensure continuous favorabledirection of the water as the stagnation point of the blades varies.Specifically, the stagnation point of the blades at any givenpoint—which is the target point for incoming water flow direction asdescribed above—varies with water flow velocity and core rotationalspeed. The pivoting front flow director 2030 allows variability to therelease point of water from the flow director such that the releasepoint may be altered in response to changes to the stagnation pointthroughout operation of the apparatus. The natural fluid dynamicsproperties of the system during operation are such that the tips 2085 ofthe front flow director 2030 will naturally follow the changingstagnation point during operation (i.e., no external interference isrequired to maintain a desirable orientation of the pivoting front flowdirector).

A pivoting front flow director also renders embodiments of the presentdisclosure suitable to dual-directional (or tidal) flow. FIG. 30A showshow the segments 2055, 2057 of the front flow director 2030 may pivotabout pivot point 2050 to reverse the direction of the V-shaped openingto allow back flow passed the flow director 2030 when the direction ofwater flow changes from Y to Y′. Two front stoppers 2080, 2082 are alsoprovided and shown specifically in FIG. 30B to prevent each segment2055, 2057 of the front flow director 2030 from pivoting beyond adesired position, which may impede rotation of the central cores 2015,2017 in the desired direction. Similarly, the first secondary flowdirector 2040 is also comprised of two rear stoppers 2090, 2092, whilethe second secondary flow director 2042 is also comprised of two rearstoppers 2094, 2096. Such stoppers 2090, 2092, 2094, 2096 also preventthe secondary flow directors 2040, 2042 from rotating beyond a desiredposition, which may reduce the efficiency of the apparatus.

Although a pair of central cores 2015, 2017 are shown in many of theillustrative embodiments of the present disclosure, additional corescould be provided to help capture residual energy from water exiting thesides of the embodiments described herein. For example, as shown in FIG.30C, additional cores 2015, 2017, 2020, 2022, 2025, 2027 may bepositioned in an outside trailing configuration, such that the apparatuswould form a substantially V-shaped configuration of central cores.

During the operation of embodiments incorporating bladed cores and thefront flow director as configured and shown in FIG. 30, unwantedpressure may build up behind the front flow director 2030 in the areadesignated by dotted circle P. To help alleviate this adverse pressurebuild-up, pressure relieving features—which will now be described withreference to FIGS. 31, 32, 33 and 34—may be incorporated into thevarious embodiments described herein. The apparatus 3010 is generallycomprised of a frame 3012, the frame 3012 preferably securing at leasttwo central cores 3015, 3017 and a primary flow director 3030. In thispressure-relieving embodiment, the frame 3012 is provided with anaperture 3039 (FIG. 33). The presence of the aperture 3039 causes thereto be a flow path to permit return water building up pressure behind thefront flow director in the general vicinity P (FIG. 34) to escape fromwithin the apparatus 3010. A shield 3035 affixed to the frame causeswater flowing over the apparatus to be diverted slightly more upward andaway from the aperture 3039, thereby creating a low-pressure realm onthe underside of the shield 3035. The low-pressure realm would in turnassist the flow of high-pressure water from behind the front flowdirector 3030. The construction of the shield 3035 is best illustratedin FIG. 33, which shows the apparatus 3010 of FIG. 31 with a cutaway ofshield 3035 slightly above frame 3012.

FIGS. 35, 36, 37 and 38 show an alternate embodiment showing a varianton the pressure relieving means shown in FIGS. 31 to 34. In thisvariant, the front flow director has a trailing fin 4031. Since thereturn water in this embodiment is effectively divided into two areas (Pand P′ of FIG. 38), two apertures 4038 and 4039 are provided. Anappropriately divided shield 4035 may thus be provided to cause pressuregradients and desired fluid flows paths similar to those described withreference to FIGS. 31, 32, 33 and 34. The construction of shield 4035 isbest illustrated in FIG. 37, which shows the apparatus 4010 of FIG. 35with a cutaway of shield 4035 slightly above frame 4012.

FIG. 40 shows an embodiment 5010 with a variant to the front flowdirector 5030 that provides additional means for relieving built-uppressure behind the front flow director 5030. For ease of illustration,the upper frame panel have been omitted from the embodiment shown inFIG. 40. The front flow director 5030 of this embodiment is configuredso as to permit water to flow from behind the front flow director 5030into the stream of incoming water flow. Specifically, front flowdirector 5030 has a gilled configuration that both maintains asubstantially smooth flow path surface for incoming water flow and sucksout high-pressure water built up behind the front flow director 5030.Similar to the low-pressure realm created under the shield of theembodiment shown in FIG. 31, incoming water flow over slots 5036 of thefront flow director 5030 also creates a lower pressure realm, whichinduces flow of water from behind the front flow director 5030 to jointhe incoming water stream. Positioning of slots 5036 may be maintained,for example, by mechanically affixing the plurality of front flowdirector components with the frame (upper frame panel not shown); byattaching the front flow director components to one another with rigidlinkages to maintain slot spacing; by other means that would beappreciated in the art, or; by any combination thereof.

FIGS. 41, 42 and 43 show yet another embodiment of the presentdisclosure. This embodiment combines the gilled front flow director witha variant of the pressure-relieving shield from FIG. 35. In thisembodiment, apparatus 6010 is comprised of frame 6012, two bladed cores6015, 6017, gilled front flow director 6030, and shield 6035. Frame 6012is less expansive than frame 4012 (FIG. 35) and does not encompass theentire apparatus 6010. Gilled front flow director 6030 has sideenclosure panels 6040, 6042, 6044 to help contain incoming water flow.The front flow director 6030 may be widest at its mouth and may taperdown as it approaches the bladed cores to cause incoming water flow toaccelerate into the bladed cores 6015, 6017. A flow path to allow waterbuilt up behind the front flow director 6030 is permitted by theaperture 6092 created by the relative spacing of the frame 6012 and theenclosure panels 6044, 6046 of the front flow director 6030 (aperture6092 is best illustrated in FIG. 43).

FIGS. 44, 45 and 46 show a variant of a bladed core that could besubstituted into the various apparatus embodiments described herein. Thealternative central core 7015 shown has two blade members 7020, 7022extending outwardly from the center of the central core 7015. In thisvariant to the blade and core configuration, the blades aresubstantially bodyless in the sense that the structure of the blades isplate-like as opposed to having a more voluminous body. For example, ablade according to this embodiment may be contoured out of sheet metalor other suitable thin flat material sufficiently strong to hold up tothe various forces exerted on the system during operation by the waterflow. Each blade member 7020, 7022 terminates in a sharp tip end (e.g.,7053). During rotation, the tip ends 7053 define a circular travel path7060. At any point in time, the blades terminate at their tips 7053, ata point that resides along the circular travel path 7060. The blades inthis embodiment are configured so as to have a tangent line at the tip7053 of the blade that is substantially congruent with the tangent linealong the circular path 7060, at the point where the tip 7053 resides.

With specific reference to FIG. 46, a single blade of the embodimentdescribed with reference to FIGS. 44 and 45 is shown. The blades of thisembodiment may be generally described as having three adjoining sectionsand two surfaces. The three sections (an inner portion 7050, a centralportion 7055 and an outer portion 7060) and the two surfaces (the impactsurface or ram surface 7070 and the lift surface or non-ram surface7075) are identified in FIG. 46. The inner portion 7050 is nearest toand attaches to the central core 7015. The central portion 7055 of theblade 7055 begins at the end of the inner portion 7050 and is configuredsimilar to an airfoil to induce low pressure and therefore lift forcesat the lift surface 7075 of the blade 7020. The outer portion 7060begins at the distal end of the central portion 7055, extends outwardlyin a curved fashion and terminates with a sharp tip 7080. The outerportion 7060 is characterized by its tip 7080 being in the orientationdescribed previously (i.e., whereby a tangent line at the blade tip issubstantially congruent with a tangent line of the circular blade tiptravel path at the point of intersection between the blade tip 7080 andthe circular path). This combination of blade features has been found toproduce favorable power generation results.

With continuing reference to FIGS. 44, 45 and 46, the blade members7020, 7022 may optionally feature one or more fluid bypass mechanismssuch as, for example, louvers 7070 that may open and close to allowfluid to pass through the blades 7020, 7022 during certain stages ofrotation of the bladed cores. The rotation of the blades can be splitinto two cycles. The first cycle, which we will refer to as the ramcycle, is experienced by a blade when incoming water flow is actingdirectly on the impact side of the blade (as described previously withreference to element 92 in FIG. 6); this cycle can also be described aswhen the impact surface of the blade is experiencing ram. When incomingwater flow is no longer acting directly on the impact side of the blade(i.e., the blade is no longer experiencing ram), the blade is in thesecond cycle, which we will refer to as the non-ram cycle. When a bladeis in the ram cycle, incoming water flow causes the louvers 7070 toclose, thereby creating a substantially continuous blade surface againstwhich water may act. Once a blade transitions into the non-ram cycle,the louvers are caused to open (or bleed) creating bypasses for waterahead of the blade's rotation to flow through the blade (as opposed tootherwise getting swept up and displaced by the blade). In this way, theblades experience less rotational resistance while in the non-ram cycle,thereby enhancing power-generating rotation of the cores.

FIG. 47 shows the steps of a method for extracting energy from a flow ofwater using the apparatus embodiments described herein. The steps of themethod may be performed in any practical order and should not be limitedto the order suggested in the exemplary embodiments described herein. Inone step 1070, an energy extraction apparatus according to any of theembodiments described herein is positioned or deployed in a body ofwater. As described, this may be achieved by tethering the apparatus tothe floor of the body of water (in the case of a buoyant apparatus) orsuspending the apparatus from a support structure at one or more pointsabove the surface of the water (in the case of an apparatus that is atleast partially non-buoyant). In either case, the apparatus ispositioned so that the core portions are submerged in water such thatthe flowing water causes rotation of the cores. In another step 1072,the apparatus is operated such that mechanical rotational energy fromthe cores of the apparatus is converted into electricity. This may beachieved, for example, through the use of generators in communicationwith the rotating cores either directly or through various mechanicalpower transmission components commonly known in the art (as previouslydescribed). In another step 1074, the generated electricity istransmitted to be used to power any number of electrical devices and/ormay be used to create or supplement one or more power grids.

Many modifications of the embodiments described herein as well as otherembodiments may be evident to a person skilled in the art having thebenefit of the teachings presented in the foregoing description andassociated drawings. It is understood that any such modifications andadditional embodiments are captured within the scope of the contemplateddisclosure, which is not to be limited to any of the specificembodiments disclosed.

What is claimed is:
 1. A blade for use with an energy-generatingturbine, the turbine having a central rotating member, the blade havinga ram surface and a lift surface, the blade comprising: an inner portionproximate the central rotating member; a central portion beginning at adistal end of the inner portion; and, an outer portion beginning at adistal end of the central portion and terminating in a sharp tip;wherein the central portion is curved to induced lift to the liftsurface of the blade; and wherein a curvature of the outer portion atthe tip substantially corresponds to a curvature of a circular pathtravelled by the tip of the blade during rotation of the centralrotating member.
 2. The blade of claim 1 wherein the blade is rotatablethrough a ram cycle and a non-ram cycle, the blade further comprising aplurality of fluid flow-through mechanisms for alleviating pressureagainst the blade while rotating through the non-ram cycle.
 3. The bladeof claim 2 wherein the plurality of fluid flow-through mechanismscomprise a plurality of louvers.
 4. The blade of claim 3 wherein theplurality of louvers are configured to close when the blade rotatesthrough the ram cycle and to open when the blade rotates through thenon-ram cycle.